July 19 (Reuters) - Wall Street was set to open lower on Thursday after eBay and American Express reported disappointing results and trade tensions rose on news the European Union may retaliate if United States slaps tariffs on EU cars.

EU Trade Commissioner Cecilia Malmstrom said she hopes a mission to Washington will ease the trade dispute that started after the U.S. imposed tariffs on EU steel and aluminum on June 1, with President Donald Trump threatening to extend them to cars and car parts.

“Today’s theme is trade war, as the EU is going to retaliate against car tariffs and that is going to weigh,” said Peter Cardillo, chief market economist at Spartan Capital Securities in New York.

“The market is probably going to be defensive even though we are getting good news on the economy and as earnings continue to pour in.”

Concerns about the impact of tariffs have been rising among manufacturers in every one of the Federal Reserve’s 12 districts, a central bank report released on Wednesday showed.

However, White House trade adviser Peter Navarro on CNBC downplayed tariff-related concerns saying President Trump’s trade strategy with China, which includes levying new tariffs, is not as disruptive as many describe.

On the earnings front, shares of AmEx fell 3.2 percent in premarket trading after the credit card company said expenses rose due to higher spending on its rewards program.

Overall earnings at S&P 500 companies however continues to be encouraging. Of the 48 companies that have reported, 87.5 percent have topped analysts’ expectations, according to Thomson Reuters I/B/E/S.

Solid earnings from major financial and industrial companies on Wednesday sent the benchmark index to its highest in more than five months, while the Dow Jones Industrial Average climbed for a fifth session.

At 8:39 a.m. ET, Dow e-minis were down 85 points, or 0.34 percent. S&P 500 e-minis were down 7.75 points, or 0.28 percent and Nasdaq 100 e-minis were down 23 points, or 0.31 percent.

Lower crude oil prices also weighed on the markets. Prices fell after official data showed an unexpected rise in U.S. crude stockpiles, U.S. output hit a record high and major oil exporters increased production. Among other stocks, IBM rose 2.1 percent after its results topped estimates due to growth in its higher-margin businesses including cybersecurity and cloud computing.

Travelers Cos shares fell 3.5 percent after the insurer missed quarterly profit estimates due to higher catastrophe losses from storms in several U.S. regions.

Danaher rose 5.6 percent after the medical device maker said it plans to spin off its dental business into a publicly traded company. (Reporting by Amy Caren Daniel in Bengaluru; Editing by Arun Koyyur)